A truck bomb exploded near the offices of a major Kurdish party in the Iraqi town of Sinjar on Wednesday, killing at least 15 people and wounding 30, the local mayor said.
Kurdish official Dakhil Kassim Hassun said the blast targeted the offices of the Kurdistan Democratic Party in Sinjar, close to the Syrian border in northern Iraq.
The group led by al-Qaida's leader in Iraq, Abu Musab al-Zarqawi, said in an Internet statement that it had carried out the attack.
Meanwhile, police in Baquba, a mixed Shia and Sunni town 65km north of Baghdad, said one policeman was killed and at least eight people wounded on Wednesday when armed men opened fire on the local offices of three parties contesting on Sunday's polls.In the northern city of Mosul, a video filmed by fighters showed three Iraqi men who had apparently been taken captive. They said they worked for Iraq's electoral commission in the city.
In the video, a masked fighter carrying a pistol read out a statement as another one crouched with a rocket-propelled grenade launcher on his shoulder.
"We are mujahidin in the province of Ninawa. What they call elections have no basis in the Islamic religion and that's why we will hit all election centres," the statement said.
Several groups in Iraq, including fighters loyal to Abu Musab al-Zarqawi, have declared war on Sunday's elections, vowing to attack polling stations and to kill those who dare to vote.
Iraqi soldiers captured
Late on Wednesday evening, four Iraqi soldiers were seized in the western city of Ramadi as they were leaving a US military base, police said.
Extraordinary security measures
are being taken to protect voters
"The four soldiers were captured by gunmen between the towns of Baghdadi and Hiyt," some 160km west of the capital, a local police officer said on condition of anonymity.
He added that no group had yet claimed responsibility for the abduction.
Hundreds of Iraqi soldiers and policemen have been killed, attacked and kidnapped, as armed groups step up their campaign against the country's security forces in the run-up to next Sunday's general elections.
Spate of attacks
Aljazeera has learned that on Wednesday a bomb, planted on the road leading to Baghdad airport and targeted at a US military convoy, damaged a US military Humvee.
In other developments of the day, US forces detained 23 people in the central Iraqi town of Ramadi and surrounded al-Bu Fahad village west of the town to carry out search campaigns.
West of Baghdad, Abu Ghraib prison came under mortar attack and sirens were heard from inside the prison following the incident.
In Tikrit, a car bomb targeting a US military convoy went off in the centre of the town.
Elsewhere, armed fighters attacked five electoral centres - in Khalis, Dhiluaya and Alam districts. And in Baiji, 11 school headmasters have stopped their school premises from being used as electoral centres for fear of attacks.
The government has announced extraordinary security measures to try to protect the polls, including closing Baghdad airport and land borders over the election period, extending night curfews in cities and banning cars from roads on election day.
In an unverified audio tape, al-Zarqawi, a Jordanian with a $25 million US bounty on his head, said the election was a plot by Washington and Iraqi Shia allies against Sunni Arabs.